Backlight Unit Diffusion Sheet Color Patterns
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Solution Overview
Problem
Conventional liquid crystal display (LCD) backlight units fail to achieve uniform mixing of red, green, and blue light emitted from light sources, resulting in reduced image quality due to incomplete light mixing near the light source area.
Innovation Solution
Incorporating a diffusion sheet with color patterns, such as red, green, and blue patterns formed from inks or fluorescence materials, positioned outside the active area adjacent to the corresponding light emitting diodes, which diffuse and mix the light effectively, improving luminance and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If red, green, and blue light emitting diodes are positioned close to the light guide plate without color patterns, then the structure is simple and manufacturing is easy, but the light mixing quality is poor and image quality is reduced
Solution Approach 1:
The diffusion sheet is designed with different regions having different properties: a first region with a first wavelength range (e.g., red-converting phosphor) positioned near the red LED, a second region with a second wavelength range (e.g., green-converting phosphor) near the green LED, and a third region with a third wavelength range (e.g., blue-converting phosphor) near the blue LED. This local differentiation of optical properties enables effective light mixing while maintaining structural simplicity
Solution Approach 2:
A diffusion sheet containing wavelength-converting phosphors is introduced as an intermediary component between the multi-color LED and the light guide plate. This diffusion sheet converts the discrete red, green, and blue light into corresponding wavelength ranges that can be effectively mixed in the light guide plate, thereby improving light mixing quality without complicating the overall structure
2Manufacturing precision
If color patterns are added to the diffusion sheet to improve light mixing, then light mixing quality and image quality are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The diffusion sheet combines multiple functions into a single component: it acts as both a light diffusion medium and a wavelength conversion layer. By integrating the phosphor materials directly into the diffusion sheet matrix, the patent merges the light scattering function and the spectral transformation function into one element, avoiding the need for separate color filtering or conversion components
Solution Approach 2:
The diffusion sheet is constructed as a composite material system incorporating transparent resin matrix with dispersed phosphor particles of different wavelength ranges. This composite structure enables simultaneous light diffusion and wavelength conversion properties within a single material layer, improving light mixing quality without adding discrete optical components
3Manufacturing precision
If color patterns are formed on or inside the diffusion sheet, then the light mixing quality is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The diffusion sheet is segmented into multiple functional regions, each containing phosphors with specific wavelength ranges corresponding to nearby LEDs. This segmentation is achieved by positioning different phosphor materials in distinct zones within the diffusion sheet, allowing each region to optimize light conversion for its local LED source while contributing to overall uniform mixing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the quality of mixed light by converting red, green, and blue light into yellow, cyan, and magenta, allowing for better mixing and generation of clear white light, thereby improving the overall image quality of the LCD.
Implementation Method 1
a diffusion sheet on the light guide plate, wherein the diffusion sheet comprises a plurality of color patterns
Implementation Method 2
the color patterns may comprise color inks or fluorescence materials
Implementation Method 3
the color patterns may comprise color inks or fluorescence materials
Implementation Method 4
the color patterns may comprise color inks or fluorescence materials
Data Source
AI summary
A backlight unit including a light guide plate, a light source comprising a plurality of color light emitting diodes, and an optical member comprising a diffusion sheet on the light guide plate, wherein the diffusion sheet comprises a plurality of color patterns that are located outside of an area that overlaps with an active area, where each of the color light emitting diodes is positioned in an area adjacent to the color pattern of a different color, and a liquid crystal display including the same are disclosed.